1. Technical Field
This invention relates generally to encapsulated flip chips and more particularly to a flip chip package having a thermally conductive member encapsulated with the flip chip.
2. Background Art
Flip chips are small semiconductor dies having terminations all on one side in the form of solder pads or bump contacts. Typically, the surface of the chip has been passivated or otherwise treated. The flip chip derives its name from the practice of flipping, or turning, the chip over after manufacture, prior to attaching the chip to a matching substrate.
Flip chip packages require a cover of some type over the silicon chip to protect it and to provide a large flat surface for pick-and-place operations. However, any cover or encapsulant above the chip increases the thermal resistance path to an ambient environment and, hence, the operational temperature of the chip.
Thermally conductive caps have also been provided for flip chips. Typically, a capped chip has a thin layer of a thermally conductive grease between the chip and the cap. However, it has been found that during thermal cycling, the grease has a tendency to be pumped, or displaced from the interface between the chip and the cap, thus increasing the thermal resistance of the interface.
The present invention is directed to overcoming the problems set forth above. It is desirable to have a flip chip package that provides low thermal resistance, and is economical to manufacture. It is also desirable to have such a flip chip package and method of manufacture that uses conventional transfer mold techniques. It is also desirable to have such a flip chip package that does not require the presence of a thermally conductive grease between the chip and a heat conducting member.